Grammar Rules Do Change |
The Blue Book of Grammar and Punctuation

Rules Do Change

Spacing after periods, colons, question marks, and exclamation marks

Originally, typewriters had monospaced fonts (skinny letters and fat letters took up the same amount of space), so two spaces after ending punctuation marks such as the period were used to make the text more legible. However, most computer fonts present no difficulty with proportion or legibility, so use just one space after a period, colon, question mark, or exclamation point at the end of a sentence. You will not be struck by lightning, we promise!

Quotation marks and punctuation

In several English-speaking countries other than the USA, a period used with quotation marks follows logic.


Myrtle said the word “darn”.
The period is outside the quotation marks because only the last word was quoted, not the entire sentence.

Myrtle said, “I would never say that.”
The period went inside the quotation marks because this was Myrtle’s entire statement.

Today, in American English usage, the period always goes inside the quotation marks.


Myrtle said the word “darn.”
This does not follow logic, but it makes life easier for those of us who have enough to think about besides punctuation.

Forming plurals in English

As time has gone on, we have shortened some words and dropped the former plural form.


The words memo and memos used to be memorandum and memoranda.

With the word data, we no longer see the singular datum used at all. Data is now often seen with both singular and plural verbs, although the word is considered strictly plural by purists.


The data are being tabulated.

The data is useful to the scientists.

Yet other words still retain their original spelling and plural form.


curriculum (singular) and curricula (plural)

Beginning sentences with butandbecause

In “the old days,” you may have been scolded for starting a sentence with butand, or because. But you wouldn’t have deserved that scolding. If you start sentences with these words, it’s usually a good idea to follow them with independent clauses.


But she would never say such a thing!

Because of this bee sting, my arm is swollen. 

If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.

15 responses to “Rules Do Change”

  1. Kamal Taylor says:

    I took typing in class in high school (it was required in 1982), and while there was no doubt as to the need of using two spaces after a period as you well documented in your article, my typing teacher did say that the extra spaces after a period more cleanly delineated the end of a sentence to make reading easier. He was right, and I’ve found this is even more true today. The crowded fonts (designed to save ink as well as paper) make reading a chore. Try reading the same article with single and then with double spaces, and see if you can note which is easier. I think you will find that the old rule, while initially bespoke for typewriters (they were bloody awful machines to work on), is much more adaptable than you think.

    I’m not a pedant, but to say that the rule has changed is a rather abrupt end to a common practice. Was there debate before approving this rule change? I don’t remember hearing about it. If there was a discussion, I am sure me and my high school typing teacher would have thrown our two cents in.

    I have been castigated mercilessly for putting in two spaces after a period when marking the end of a sentence. I realize that this convention upsets many people for some reason, though I don’t share that sentiment when others leave one space. Yet the vitriol that us two-spacers receive is akin to being perceived as a Luddite, hell-bent on proselytizing all of you one-spacers. Well finally, here is some scientific proof, This details the efforts by scientists to study whether it was easier to read with one or two spaces and the answer, drumroll please, is it is easier with two spaces. Done. Case closed. I am no longer the Troglodyte. This news has been hard to accept for many one-spacers out there, particularly this poor soul writing in The Atlantic,

    Love your column. Thoughts?

    • We appreciate the positive feedback. The convention changed quite a while ago. You can read more about it at Wikipedia.
      In a reply on the Q&A page regarding this topic, The Chicago Manual of Style said: “I’m so sorry to report that that ship sailed long ago. You are a lone voice, crying in the wilderness. Too little, too late; a bolted horse, a dollar short. No metaphor can express how hopeless this is. Our best advice to you is to look for a silver lining in the single space.”
      Nevertheless, as you’ve mentioned, serious research continues on this topic. See also the Washington Post article mentioned by Anne P. in her May 14, 2018, comment.

    • Jeanne Daneils says:

      I was a typesetter (and graphic designer) for over 25 years. I too learned in high school in the 1960s to double-space after a period.

      When I began to typeset, it was a very difficult habit to break. But, when you are typing something to be justified (straight left and right sides), double-spacing can cause issues when the typesetting program adds space where hard spaces have been used.

      With many typesetting programs, space to make a line of type justified was first added to hard spaces, and then, in good computerized typesetting, it was also added inter-letter (if necessary) in justifying the line. The double spaces after a period would cause some really wide white spots in justified text, especially if the typesetting program only added inter-word spacing using hard spaces. So, there was a reason why double spaces fell out of use when typewriters did.

      I correspond with a lot of people my age who still double-space, and I
      never call them on it because I understand why they do it. Unless they
      were writing their emails in a justified format, it makes absolutely no

  2. Tom Saywell says:

    I have always thought that alumni was plural, and alumnus was singular. I notice recently that “alumni” appears to be used as both or either — especially on all of those car license plate frames.
    What do you know about this?

    • The following distinctions are correct according to The AP Stylebook:
      Use alumnus (alumni in the plural) when referring to a man who has attended a school.
      Use alumna (alumnae in the plural) for similar references to a woman.
      Use alumni when referring to a group of men and women.

  3. Virginia M. says:

    I appreciate this very much. It’s hard for someone with decades of experience proofreading to keep up with new rules.

  4. Anne P. says:

    I happened to see an article in The Washington Post, dated May 4, about the single or double space at the end of sentences. The article discusses a scientific study on reading comprehension relative to single or double spacing after full stops, predictably focusing on periods. Interestingly, the longer space between sentences, even with proportional type, seems to help readers understand what they’re reading.

    You might find the article worth reading, just as a footnote to summaries of current practices in typesetting. Of course, the combined space that publishers save by eliminating the second space translates into saving pages in each book, which then translates into lower publication costs. I wonder to what extent the publishers have advocated the single space after full stops for financial rather than for other reasons.

  5. Cheryl A Bramsen says:

    Has the rule changed to put a comma after and at all times?

    • says:

      Our Rule 1 of Commas has not changed recently. However, as our post Commas Before and in a Series states, “Newspapers and magazines do not generally use this rule as print space is too valuable to use on what might be considered extraneous punctuation.”

  6. D. Ucci says:

    While “rules” do change, sometimes this happens not for any good reason(s). I like the old rules, which when learned, do not cause issues. It is sad to seek them go. As a retired professor in a technical field, I still use the “old” rules for clarity of thought. I agree with the comments above from the various respondents for keeping them as they were; though in some instances I can see the value of using some of the new rules (such as using conjunctions to begin a sentence allowing poetic (or prosaic) license to emphasize a point (though generally not in technical writing).

  7. Roy Warner says:

    Thank you. I follow your column. I’m a 75-year-old retired NY trial lawyer now living out West. Although I stopped trying cases years ago, I still do appellate work as counsel to the NY Bar. You’ve taken a load off my shoulders with your advice that periods should now always be within the ending quote; I’ve been using the old-fashioned method until right now.

  8. Buckley says:

    RE “…most computer fonts present no difficulty with proportion or legibility, so use just one space after a period, colon, question mark, or exclamation point at the end of a sentence,” point taken; but I’ll still use two spaces after ending punctuation marks because it aids readability.

  9. Karen Burzdak says:

    I completely agree with any commenter who states that it is easier to read text when there are two spaces between the end of a sentence and the beginning of the next one. When I have to read something over twice–such as in this situation–I am frustrated that I have to do just that.

    I will continue to use two spaces!

  10. Rebecca Henry Lowndes says:

    RE: Quotation Marks and Periods

    As an American writer, I deem it no hardship to distinguish between a quote that’s a full sentence and one that’s a single word or a phrase. I don’t care what the American *convention* is — I’m sticking with the logic-based practice of putting the period where it actually belongs, not where its placement might require no thought whatsoever.

    Furthermore, I use British spellings when I find them appealing. No apologies.

    PS I was never taught to insert two spaces after the end of a sentence so, mercifully, that’s one rule I don’t have to push back against.

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